Electronic relay transmitter and receiver self-synchronous system



Feb. 15. 1949. B. J, BAECHER 2,461,511

ELECTRONIC RELAY TRANSMITTER AND RECEIVER SELF-SYNCHRONOUS SYSTEM FiledDec. 26, 1945 2 Sheets-Sheet l grwm'vfob BERNARD J. BAECHER '1 Feb. 15,1949. J, BAECHER 2A1 5H ELECTRONIC RELAY TRANSMITTER AND RECEIVERSELF-SYNCHRONOUS SYSTEM Filed Dec. 26, 1945 2 Sheets-Sheet 2 FIG.2

BERNARD J. BAEGHER Patented Feb. 15, 194

ELECTRONTC RELAY TRANSMITTER AND RECEIVER SELF-SYNCHRONOUS SYSTEMBernard J. Baecher, Brooklyn, N. Y.

Application December 26, 1945, Serial No. 637,294

(Granted under the act of March 3, 1883, as amended April 30, 1928; 3700. G. 757) 1 Claim.

of that supplied by the transmitter switch in a remote positioningsystem.

A common type of step-by-step positioning system, for example, the typeused on shipboard for compass repeater systems, consists of a rotaryswitch at the transmitting end controlling a ro tary magnetic element atthe receiving end. In operation potential is successively applied to aplurality of contacts each corresponding to a pair of aligned coils atthe receiving end. Energize.- tion of a set of such coils causes arotatable magnetic armature to move toward an aligned position andsimultaneously to turn a remote indicating scale.

Where a large number of remote indicating devices must be used, or wherethe remote device requires a considerable amount of electrical power,

the power requirements ma exceed that which can be handled by the switchlocated at the transmitter. While it is possible that a heavy dutyrotary switch could be used at the transmitter end in order to handlethe required current, this has been found tobe impracticable. Buildingsuch a switch of an increased rating necessarily increases the amount ofmechanical power required to drive it; however, the means generallyavailable to drive the switch are of limited power Further, the handlingof large currents at relatively high voltages results in arcing at theedges of the fixed contacts. maintenance of such contacts, such arcingis also disadvantageous since it necessitates an increase in spacing ofthe contact sectors. The latter is undesirable since it increases theproportion of the time during which no positioning coil is energized atthe receiver end.

Magnetic relays have been used to increase the power controlled by thetransmitter switch. The use of relays is an improvement since largercurrents and higher voltages may be handled than are possible withoutusing relays. Relays, however, suffer from the disadvantage of being of'relatively high inductance which appreciably limits Besides increasingthe l the maximum speed of the system to that well.

below the speed of response of the relay. In addition, the use of relaysgives rise to problems of contact maintenance and adjustment. Relayssuffer from the further disadvantage that wear of the moving parts tendsto change the characteristics with age. The use of relays is furtherobjectionable from the standpoint of noise and vibration. As mentionedabove, it is necessary that at least one of the sets of positioningcoils at the receiving end he energized at any given instant, requiringa matching of relay characteristics.

The above disadvantage of using relays I have discovered can besatisfactorily overcome by employing grid-controlled rectifiers as arelaying means.

It is an object of my invention to provide a relaying device which willcontrol comparatively large amounts of electrical power by means ofcontrol currents of small magnitude.

In accordance with my invention a remote positioning system is providedwhich will handle large amounts of electrical power without maintenanceproblems normally associated with magnetic relays and contacts.

Further in accordance with my invention, a remote positioning system isproduced having extremely rapid response as compared to systems in whichmagnetic relays are utilized.

In accordance with one aspect of my invention, a remote positioningsystem is produced in which the electrical leads leading from thetransmitter to a remote point may be of limited capacity while stillenabling 'the control of a relatively large amount of power at thereceiving end.

Further in accordance with my invention, a

relaying system for remote positioning is produced having particularapplicability to deadreckoning devices.

My invention also resides in features of construction, combination andarrangement herein described or disclosed.

In the drawings:

Figure 1 shows one embodiment of my invention in which grid-controlledrectifiers connected for half-wave rectification are used in astep-bystep relaying system.

Figure 2 shows another embodiment of my invention in whichgrid-controlled rectiflers are used in a full wave circuit.

In Figure 1, the number ill indicates a master shaft connected to anydevice whose position must be duplicated. Such a device may, forexample, be a master compass on shipboard. The shaft l0 controls theoperation of a transmitter switch l2, conveniently identified as thehome transmitter switch, consisting of a wiper arm l4 cooperating withthree arcuate stationary contacts or contact sectors IS. The contacts 16are respectively connected to the grids l8 of grid-controlled gaseousrectifier or hot cathode thyratron relay tubes 3 through resistances 22.The switch and relay are required to be confined to a limited space dueto their use on shipboard. The rectifiers are individuall allocated tothe respectively possible stepped positions of a positioning device 38,presently mentioned again, thereby aii'ording the advantage of easyreplacement in the event any one develops a fault. The use of tuberectifiers has the further advantage of their diminutive size, enablingthe emplacement of the entire bank of rectifiers in a space which wouldbe entirely inadequate for rectifiers of other types.

A feature of considerable importance lies in the inherent nature of therectifier tubes. As indicated in the drawings these are of the hotcathode thyratron type and, being such, are readily responsive to a lowpotential direct current source for the control of a relatively largecurrent, and desirably 'so out of consideration for keeping weights downwherever possible. The rapidity with which a thyratron is capable ofdeionizing after each impulse, due to the low direct current gridpotential, makes it particularly well adapted to the instant systemwherein it is desirable to have the thermionic relay ready itselfpromptly for the successive step positions which, in some instances, maybe required to occur in fairly quick order. A path is also providedthrough resistances 24 to a point of zero potential 25. Included withinthe grid-controlled rectifiers are filaments 28 energized by windings 30of transformers not shown. The filaments are connected to a variablesource 32 of low D. C. potential. The wiper arm I 4 of switch i2 isconnected to a source 34 of somewhat higher D. C. potential.

The plates 36 of the rectifier tubes are connected to windings 38 of theremote positioning device 39 which act in diametrical pairs to produceradially-aligned flux. Cooperating with the windings 38 is a rotatablemagnetic element 48 which is coupled to an indicating or similar devicesuch as a scale 42. The coupling preferably includes suitable gearing 4|whereby one turn of the indicating device 42 corresponds to many turnsof the magnetic armature 4G. The circuit is completed through a sourceof alternating current indicated at 44. Condensers 48 may be used, ifdesired, to help smooth out the D. C. pulses.

In operation, the wiper arm H is caused to apply positive potential tothe grids I 8 of the rectifiers 28. Under conditions when no positivepotential is being applied to the grids, the grids are slightly negativewith respect to the cathode 28 and no conduction takes place. Aspositive potential is applied to the grid of a given tube, however,pulses of current fiow from cathode 28 to anode 36 during the time thatthe anode 36 has a positive potential. Upon removal of the exciting gridpotential, as the wiper arm passes on to the next segment, conduction inthe particular tube will cease immediately that the voltage applied tothe anode next passes through zero,

Subsequent application of positive grid potential to the other tubeswill cause current to flow in the anode circuit and consequently throughthe coils 38 of the positioned device. The outer periphery of therotatable element 40 is formed so that the transfer of fiux from onediametrical set of coils to the adjacent set of coils results in smoothrotation of the magnetic element.

It is unnecessary that the angular relationship of the wiper arm Id ofthe switch l2 and the rotatable element in the positioned device bemaintained exactly, it is necessary merely that the step-by-step actiontake place in a positive manner. While the sudden transfer of currentfrom one set of coils 38 to an adjacent set of coils will cause a.stepped rotational movement of the element d8, since the indicator 42 isnormally geared down with respect to the rotatable element 50, suchirregular movement will not be noted in the indicator device.

Figure 2 is the modification of the device shown in Figure l in whichthe full wave rectification is utilized. In this modification,additional gridcontrolled rectifiers 68 are connected in push-pullrelation with respect to the rectifiers 28. Alternating potential isapplied to the anodes 38 of the rectifiers 20 and d8 by means ofseparate center-tapped coils 50 on anode supply transformer 52.

In Figure 2 are also shown variable resistances 54 connected to thegrids of each of the pairs of rectifier tubes. Such resistances are usedto match the characteristics of each of the three pairs of rectifiertubes and to compensate for any difference between the voltages producedby the anode supply windings 5B.

The operation of this modification is practically the same as thatalready outlined in connection with Figure 1. In this case, however,application of positive potential to the grids of a pair of rectifiers20 and 58 will cause a fully rectified pulsating direct current to fiowin the line associated with the pair of rectifiers. The cooperativeoperation of rectifier tubes 20 and 38 to produce full waverectification is well known to one skilled in the art. An advantagegained by full wave rectification is the more constant energization ofthe coils 38 in the positioned device 33 and consequently greater torquecapabilities.

It will be noted that the contact sectors it of the control switch I2are located in closely adjacent relation. Such close spacing is possiblebecause of the extremely low voltage and current required by the gridsof the rectifier tubes. This close spacing together with the use of aroller type wiper arm insures that one of the sets of the coils 38 inthe positioned device will be energized at all times. Also, because ofthe low voltage and current required to be handled by the control switchI2, the moving parts of such switch may be made extremely light thusputting a very small friction and inertia load on the master shaft ill.

The use of the remote-positioning relaying system disclosed enablesconductors leading from the transmitter switch i2 to the positioneddevice 39 to be of extremely light cross section, provided that thegrid-controlled rectifiers are located near the remote or receiverportion of the device.

It will be seen from the above that I have provided a remote positioningsystem which will handle large amounts of power, which is rapid inresponse since it involves no moving relay parts, and which entails aminimum of maintenance and adjustment.

While I have shown and described but two embodiments of my invention, itwill appear to those skilled in the art that various changes andmodifications may be made without departing from my invention, and Itherefore aim in the appended claim to cover all such changes andmodifications as fall within the true scope of my invention.

The invention described herein may be made or used by or for theGovernment of the United States for governmental purposes without thegizing coil and the energizing coils of each of said A pairs beingserially connected, the electromagnetic devices in each of said pairsbeing diagonally and radially disposed about an axis, the said severalpairs being in consecutive sequence and at equiangular positionsrelative to each other, with the inner ends of the said electromagneticdevices tangent to a circle enclosing a circular area about said axis,means connecting corresponding ends of said serially connectedenergizing coils to one terminal of :a source 01' alternating current,means connecting the remaining ends of said serially connectedenergizing coils to the anodes of said electronic tubes, respectively,means connecting the cathodes of said electronic tubes to the otherterminal of the source of alternating current, biasing means forrendering said electronic tubes normally nonconducting, a source ofpotential of suflicient magnitude to render said tubes conductingconnected between the cathodes of said tubes and the movable arm of saidswitch, means connecting said spaced contacts of said switch to thecontrol grids of the tubes respectively in consecutive order, a magneticarmature supported within the circular space between the inner ends ofsaid electromagnetic devices and pivoted about the axis thereof, andmeans mechanically con necting said armature with the device to bepositioned, whereby the magnetic armature is caused to assume a positiondetermined by the tube rendered conducting by said switch.

BERNARD J. BAECHER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,902,131 Kern Mar. 21, 1933 252,168,170 Mittag Aug. 1, 1939 2,225,032 Carbonara Dec. 17, 19402,355,727 Holters Aug. 15, 1944

